Massive police raids in Middlesbrough led to 11 people being arrested for drug dealing, money laundering and immigration offences.

The series of raids on 11 properties started yesterday at 10am when Cleveland Police hit an empty business address in Longlands Road, Middlesbrough.

Officers in chemical protection suits and gas masks forced entry to the building and found an “industrial-scale” cannabis farm before arresting three men aged 34, 42 and 49.

As reported in later editions of yesterday’s Gazette, the Longlands area of the town ground to a standstill as dozens of officers took part in the operation.

A plastic inflatable room believed to be used to spray people for decontamination was also present at the scene.

Colleagues from the fire and ambulance services, as well as gas and electricity personnel, were on standby. Police said they were uncertain of the condition of the building and there was a risk of unsafe power connections.

Following this initial raid, a further 10 addresses across Middlesbrough were targeted throughout the day.

Another eight arrests were made including seven men aged 18, 22, 26, 29, 44 and two 32-year-olds. One woman aged 36 was also arrested.

Colleagues from the Immigration Service were notified regarding some of the prisoners.

Scott Marshall, 17, from South Bank, was leaving Middlesbrough College, where he is doing a plastering course, when he saw the first Longlands raid.

He said: “I was walking out when I saw all the police. I’ve never seen anything like it. There were so many of them. No-one seemed to know what was going on.

“I saw the police go into the house. They had to hit the door a few times before they got it open. Then they all ran in. They looked like they had gas masks on or something like that and three people were brought out.”

Another Longlands resident, who asked not to be named, said: “There has been some activity in that area lately but you never know if it’s something you should know about.

“This area is quiet generally. We have had the odd drugs raid over the years but very rarely. Everyone has just been shocked to see something that looks so major happening on their doorstep.”

One of the raids saw a shop in Parliament Road searched with sniffer dogs.

Police swooped on K&S Communications, a mobile phone shop in Parliament Road, and the flat above it as residents and shop workers looked on from their doorways.

One man was seen being bundled into a police van after several police vehicles arrived.

The shop remained closed throughout the day as police continued their investigations.

“They just shut the shop and went in,” said one shop owner, who did not want to be named.